1. Field of the Invention
The present invention relates generally to agricultural harvesters such as combines, and more particularly to feeder housing transition cones of threshing or separating systems in such combines, and still more particularly to vanes on the inner surfaces of the transition cones.
2. Description of the Related Art
An agricultural harvester known as a “combine” is historically termed such because it combines multiple harvesting functions, such as picking or cutting, threshing, separating and cleaning in a single harvesting machine. A typical combine includes a header which removes the crop from a field, and a feeder housing which transports the crop matter into a threshing rotor. The threshing rotor rotates within a perforated housing, which may be in the form of adjustable concaves, and performs a threshing operation on the crop, to dislodge the grain from other crop material. Once the grain is threshed, it falls through perforations in the concaves onto a grain pan. From the grain pan, the grain is cleaned on sieves in a cleaning system. A cleaning fan blows air through the sieves to discharge chaff and other debris toward the rear of the combine. Non-grain crop material, such as straw from the threshing system, proceeds through a residue system, which may utilize a straw chopper to process the non-grain material and direct it out the rear of the combine. The cleaned grain is transported to a grain tank onboard the combine. When the grain tank becomes full, the combine is positioned adjacent a vehicle into which the grain is to be unloaded, such as a semi-trailer, gravity box, straight truck, or the like; and an unloading system on the combine is actuated to transfer the grain from the grain tank into the vehicle.
More particularly, a rotary threshing or separating system includes one or more rotors which can extend axially (front to rear) or transversely (side to side) within the body of the combine, and which are partially or fully surrounded by a perforated concave. The crop material is threshed and separated by the rotation of the rotor within the concave. Coarser non-grain crop material such as stalks and leaves are transported to the rear of the combine and discharged back to the field. The separated grain, together with some finer non-grain crop material such as chaff, dust, straw, and other crop residue are discharged through the concaves and fall onto a grain pan where they are transported to the cleaning system. Alternatively, the grain and finer non-grain crop material may also fall directly onto the cleaning system itself.
The cleaning system further separates the grain from non-grain crop material, and typically includes a fan directing an airflow stream upwardly and rearwardly through vertically arranged sieves which oscillate in a fore and aft manner. The airflow stream lifts and carries the lighter non-grain crop material towards the rear end of the combine for discharge to the field. Clean grain, being heavier, and larger pieces of non-grain crop material, which are not carried away by the airflow stream, fall onto a surface of an upper sieve (also known as a chaffer sieve) where some or all of the clean grain passes through to a lower sieve (also known as a cleaning sieve). Grain and non-grain crop material remaining on the upper and lower sieves are physically separated by the reciprocating action of the sieves as the material moves rearwardly. Any grain and/or non-grain crop material remaining on the top surface of the upper sieve is discharged at the rear of the combine. Grain falling through the lower sieve lands on a bottom pan of the cleaning system, where it is conveyed forwardly toward a clean grain auger. The clean grain auger conveys the grain to the onboard grain tank for temporary storage.
In combines having a rotor operating within a concave formed as a rotor cage, it is known to provide a transition cone between the feeder housing and the rotor cage. The transition cone narrows along its length, from the upstream end to the downstream end of the cone. An auger flight operated by the rotor transports the cut crop material through the transition cone, from the feeder housing to the rotor cage. It is known to provide helical vanes on the inside surface of the transition cone, to facilitate efficient transport of crop material through the transition cone. Known transition cone vanes are made from angle-iron or other L-shaped material that is additionally shaped to conform to the inner surface of the transition cone, along a generally helical or spiral path. Accordingly, each has relatively thin upstanding and base segments of consistent thickness throughout. A plurality of vanes may be used in each transition cone. The transition cone vanes operate to direct and orient the crop material transported there along by the rotating auger flight. The L-shaped material is forwardly facing in the machine; that is, the base portion extends upstream from the upstanding portion. The vanes have been attached using threaded fasteners inserted from the inside, through the base of the cone vane and the transition cone itself. Bolts having elongated heads have been used so that the elongated head will engage the upstanding segment of the cone vane to prevent rotation of the bolt as a nut is fastened on the end of the bolt at the outside of the transition cone. Limited space in the transition cone makes the use of wrenches difficult, so the aforedescribed T-bolts have been used. However, removing and replacing vanes in the transition cone has been difficult and time-consuming because of the limited access available, and the somewhat cumbersome nature of inserting T-bolts from the inside.
During use, the crop material tends to follow along the transition cone vane and is somewhat compressed against the inside surface of the narrowing cone. Experience has shown that the greatest regions of wear occur on the inner surface of the transition cone immediately downstream from the upstanding portions of the transition cone vanes. To reduce the effects of wear, manufacturers have used hardened coatings and/or material treatments on the inside surface of the transition cone, which can add significant cost.
What is needed in the art is a vane for the transition cone in an agricultural harvester that improves the movement of crop material there along, minimizes wear and facilitates removal and installation of the vane.